Phased array antenna with phase shifter cooling

ABSTRACT

A phased array radar antenna including a plurality of individual radar emitters disposed in honeycomb arrangement and supplied through corresponding waveguides from a common source of microwaves to propagate a radar wavefront. The phases of the microwaves in the conduits are shifted to slow the waves and scan the wavefront by changing the magnetization of ferrite toroids in the conduits. Capillary means and a coolant cooperate in the conduits to remove excess heat from the toroids.

United States Paten [1 Smith Dec. 3, 1974 PHASED ARRAY ANTENNA WITH PHASE SHIFTER COOLING Scharfman 333/22 F Primary Examiner-Eli Lieberman Attorney, Agent, or Firm-Edward J. Kelly; Herbert Berl; William P. Murphy ABSTRACT A phased array radar antenna including a plurality of individual radar emitters disposed in honeycomb arrangement and supplied through corresponding waveguides from a common source of microwaves to propagate a radar wavefront. The phases of the microwaves in the conduits are shifted to slow the waves and scan the wavefront by changing the magnetization of ferrite toroids in the conduits. Capillary means and a coolant cooperate in the conduits to remove excess heat from the toroids.

5 Claims, 5 Drawing Figures PHASED ARRAY ANTENNA WITH PHASE SHIFTER COOLING BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION A microwave phase shifter incorporates a rectangular toriod of ferrite longitudinally disposed in a sealed section in each of the waveguides and secured in electrical connection with the wide sides of the waveguides. An insulated conductor loop encloses one of the remaining sides of the toroid to carry electrical current to magnetize the toroid for the phase shift. Cooling means usually disposed along the wide sides of such waveguides remove sufficient heat from the attached surfaces of the toroid. The material of the toroid, ferrite. is excellent dielectric material but a poor heat conductor so that accumulation of heat in the unattached legs of the toroid would cause the ferrite to crack and the toroid to fail or at least would change the electrical characteristics of the toroid. The walls of the spaces within the toroid and adjacent thereto are lined with connected wicking material for capillary action between the unattached walls of the waveguide and toroid. A coolant that vaporizes below the critical tent-- perature of the ferrite is selected and the wicking or grooves are saturated with the coolant. As the toroid becomes heated, the coolant is vaporized; only to be condensed again by encounter with the unattached walls of the waveguide that are provided with additional cooling coils for dissipation of the excess heat. The capillary means return the condensed coolant to the toroid to repeat the cycle.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevation of a radar antenna showing the individual emitters.

FIG. 2 is a view along line 2-2 of FIG. 1 showing the waveguides to the emitters.

FIG. 3 is a view along line 33 of FIG. 2.

FIG. 4 is a view along line 4-4 of FIG. 3.

FIG. 5 is a view similar to FIG. 3 with the capillary means including grooves engraved on unattached surfaces.

DESCRIPTION OF THE PREFERRED EMBODIMENT A radar antenna 11 includes individual emitters 13 connected by waveguides 15 to a common source (not shown) of radar waves. Waveguides 15 include lateral bulkheads or windows 17 of dielectric material transparent to microwaves to form sealed chambers 19 therebetween. A hollow rectangular core or toroid 21 substantially 10 cm long and 1 cm wide ofa 3 mm thick posed in each chamber 19 in electrical conductive enferromagnetic dielectric material such as ferrite is dis gagement with the long sides 23 of the chamber. Sides 23 are spaced substantially 1.5cm apart. An electrical conductor loop 25 is provided around an unattached side of toroid 21 for energization to magnetize toroid 21 and slow the microwaves in the core. The degree of magnetization of the waveguide cores is continuously and selectively varied to produce 20 scanning of the wavefront from antenna 11.

Resistance of the ferrite to the microwave flow plus the continual scanning produces a great deal of heat and since dielectrics such as ferrite are notoriously poor heat conductors the heat could cause a change in the electrical characteristics of the ferrite and unequal expansions in the unattached sides of core 21 would cause early failure by cracking. Cooling tubes 29 are provided on the unattached sides of waveguide 15, and wicking 30 is secured to the surfaces within chamber 19- for capillary action between the unattached sides of waveguide 15 and toroid 21.

Chamber 19 is provided with a coolant 31 to saturate wicking 30, water or freon may be used since either vaporizes below the. critical and/or cracking temperature for tor0id2l. As the antenna is operated coolant 31 vaporizes to absorb excess heat and prevent the toroid temperature from rising to the critical value. The coolant condenses on contact with the unattached walls of waveguide 15 for dissipation of the excess heat by cooling tubes 29 and the condensate is returned by capillary action through the wick to toroid 21 to repeat the cycle.

Alternately, a portion of the unattached surfaces within chamber 19 may be scribed with fine connected grooves 33 as in FIG. 5 to implement the capillary flow of the coolant.

I claim:

I. An antenna comprising a plurality of waveguides disposed in honeycomb relation and connected to a common source of microwaves to produce a wavefront; and toroidal phase shifters respectively disposed in said waveguides for selective 'control of the speed of the waves in said conduits for scanning the wavefront and wicking means lining portions of the inner surfaces of said waveguides and the outer surfaces of the toroidal phase shifters to dissipate heat by capillary action.

2. An antenna comprising: a plurality of waveguides with respective phase shifters, disposed in honeycomb relation and connected to a single source of microwaves to produce a wavefront with each of said phase shifters including a pair of lateral microwave transparent windows in sealed spaced relation with one of said conduits to form a compartment therein; toroids respectively disposed in longitudinal electrical contact with the wide sides of said compartments to provide enclosures within and adjacent said toroids and individually wound with an insulated electrical loop for magnetization of the toroid to slow the waves in the conduit; cooling coils enclosing each of said waveguides; capillary means disposed on unattached surfaces of said enclosures; and a coolant saturating said capillary means for vaporization to remove excess heat of said toroid and condensation to dissipate the excess heat to the cooling coils; said capillary means being disposed for communication to convey the coolant to said toroid for revaporization.

3. A phase shifter as in claim 2 with said capillary means comprising wicking material secured to the unattached enclosure surfaces.

tion capability to slow the microwaves in said conduits and said coolant disposed for vaporization substantially below the critical and/or cracking temperature of said material. 

1. An antenna comprising a plurality of waveguides disposed in honeycomb relation and connected to a common source of microwaves to produce a wavefront; and toroidal phase shifters respectively disposed in said waveguides for selective control of the speed of the waves in said conduits for scanning the wavefront and wicking means lining portions of the inner surfaces of said waveguides and the outer surfaces of the toroidal phase shifters to dissipate heat by capillary action.
 2. An antenna comprising: a plurality of waveguides with respective phase shifters, disposed in honeycomb relation and connected to a single source of microwaves to produce a wavefront with each of said phase shifters including a pair of lateral microwave transparent windows in sealed spaced relation with one of said conduits to form a compartment therein; toroids respectively disposed in longitudinal electrical contact with the wide sides of said compartments to provide enclosures within and adjacent said toroids and individually wound with an insulated electrical loop for magnetization of the toroid to slow the waves in the conduit; cooling coils enclosing each of said waveguides; capillary means disposed on unattached surfaces of said enclosures; and a coolant saturating said capillary means for vaporization to remove excess heat of said toroid and condensation to dissipate the excess heat to the cooling coils; said capillary means being disposed for communication to convey the coolant to said toroid for revaporization.
 3. A phase shifter as in claim 2 with said capillary means comprising wicking material secured to the unattached enclosure surfaces.
 4. A phase shifter as in claim 2 with said capillary means including narrow grooves engraved in the unattached enclosure surfaces.
 5. A phase shifter as in claim 2 with said toroid formed of a material such as ferrite having magnetization capability to slow the microwaves in said conduits and said coolant disposed for vaporization substantially below the critical and/or cracking temperature of said material. 